Process for the preparation of base oils for the production of lubricating oil

ABSTRACT

HIGH VISCOSITY INDEX LUBRICATING BASE OILS ARE PREPARED BY TREATING PARAFFINIC-NAPHTHENIC OILS HAVING A LOW AROMATIC CONTENT AND A HIGH CONTENT OF NAPHTHENES WITH CONDENSED RINGS WITH HYDROGEN IN THE PRESENCE OF PLATINUM ON ALUMINA CATALYST CONTAINING NOT MORE THAN 4% WT. OF AN ALKALI OR ALKALINE EARTH METAL AT A HYDROGEN PARTIAL PRESSURE ABOVE 10 KG./CM.2 AND A TEMPERATURE OF AT LEAST 345*C.

United States Patent O 3,730,877 PROCESS FOR THE PREPARATION OF BASEOILS FOR THE PRODUCTION OF LUBRICATING OIL Willem C. J. Quik and PieterA. van Weeren, Amsterdam, Netherlands, assignors to Shell Oil Company,New York, NY. No Drawing. Filed Dec. 5, 1968, Ser. No. 781,628 Int. Cl.(110g 23/04 US. Cl. 208-143 4 Claims ABSTRACT OF THE DISCLOSURE Highviscosity index lubricating base oils are prepared by treatingparaffinic-naphthenic oils having a low aromatic content and a highcontent of naphthenes with condensed rings with hydrogen in the presenceof platinum on alumina catalyst containing not more than 4% wt. of analkali or alkaline earth metal at a hydrogen partial pressure abovekg./cm. and a temperature of at least 345 C.

BACKGROUND OF THE INVENTION Field of the invention The invention relatesto a process for the preparation of high-viscosity-index base oils forthe production of lubricating oil by treating a paraffinic-naphthenichydrocarbon oil with hydrogen in the presence of a catalyst whichcontains platinum as active metal component.

Description of the prior art As is known it is impossible to producelubricating oils with a high viscosity index (HVI) from highlynaphthenic crude oils in a conventional manner since it is preciselythose components, viz. the paraifinic and isoparaflnic hydrocarbonsimparting good lubricity to the finished lubricating oil, whichrelatively speaking, are present in small amounts. The term HVIlubricating oils includes oils which have a viscosity index (VI) of morethan 80 according to the Dean and Davis method. It is especially thenaphthenic hydrocarbons with condensed rings, the polynaphthenes, whichhave poor lubricating properties and exercise an unfavourable influenceon the viscosity index of the finished lubricating oil. Mononaphthenesboiling in the lubricating oil range have no adverse effect.

However, if for the production of lubricating oil onlyparaffinic-naphthenic base oils with a relatively high content ofnaphthenes are available means other than those conventionally usedshould be employed in order to produce HVI lubricating oils therefrom.One of these means is a catalytic hydrogen treatment of the unsuitablebase oils under circumstances which cause the naphthenic com pounds tobe converted into non-naphthenic lubricating oil components. In this waythe ratio of the lubricating oil components to one another can bemodified in such a manner that the base oil thus treated has improvedproperties. It has been proposed in the literature to bring ahydrocarbon oil fraction which substantially boils above 285 C. andcontains naphthenes with condensed rings into contact with hydrogen inthe presence of a hydrogenation catalyst such as platinum metal on anon-acidic carrier. This is effected under such conditions oftemperature and pressure that the naphthenic compounds aredehydrogenated to aromatic hydrocarbons.

The aforementioned method of converting naphthenic compounds into otherhydrocarbons has its drawbacks. The first is that aromatic oralkyl-substituted aromatic compounds are less desirable lubricating oilcomponents because they have poor lubricity. Thus, in order to obtain alubricating base oil with improved properties the aromatic compoundsformed should be removed. However,

this involves a reduction in the yield of base oil relative to the feedused as starting material, which constitutes a second drawback. Thelatter drawback will be aggravated according as more naphtheniccomponents have been converted into aromatic components.

Another method previously proposed for the production of lubricating oilis hydrocracking of the base oil. By means of this method it isgenerally possible to improve, i.e. to raise the viscosity index of baseoils for lube oil production. However, this method cannot be continuedindefinitely because hydrocracking is a destructive method so that theresultant amount of base oil boiling in the same boiling range becomessmaller and smaller. Further, it has been found that together with thedecreasing yield the viscosity of the base oil also diminishes.

As used in this application base oil for the production of lubricatingoil is understood to mean any hydrocarbon oil or oil fraction suitablefor the production of lubricating oils. The greater part of such a baseoil boils above 300 C. and from this base oil the various lubricatingbase oils such as spindle oil, light, medium and heavy machine oil,cylinder oil and the like are obtained, which lubricating base oilsafter a possible further treatment such as colour improvement, dewaxing,etc., yield the various fractions which may serve as finishedlubricating oils either as such or after addition of additives. Baseoils having a VI of and more considered to be VHI oils; if desired theviscosity indices of the lubricating base oils can be further increasedby conventional methods.

The object of the invention is to produce base oils with ahigh-viscosity-index by starting from paraifinic-naphthenic hydrocarbonoils or oil fractions. It is a further object of the invention toconvert the naphthenic components in these oils into components whichare valuable for the lubricating properties of the lubricating oil.Another object of the invention is to improve the viscosity index of thebase oil while retaining a good viscosity.

SUMMARY OF THE INVENTION According to the process of the inventionhigh-viscosityindex base oils for the production of lubricating oil areobtained by treating a parafiinic-naphthenic hydrocarbon oil withhydrogen in the presence of a catalyst which contains platinum as activemetal component. The process is characterized in that a parafiinic oilwhich is poor in aromatics and has a high content of naphthenes withcondensed rings is contacted with hydrogen in the presence of a basiccatalyst consisting of more than 0.5% by weight of platinum on alkalimetal or alkaline earth metal-containing alumina at a partial hydrogenpressure of more than 10 kg./cm. and a temperature of at least 345 C.The catalyst preferably contains 15% by weight of platinum metal.

The feed which is used in the process according to the invention shouldbe a paraffinic oil or oil fraction which is poor in aromatics and has ahigh content of naphthenes with condensed rings. A feed of this type canbe composed by blending suitable hydrocarbon oil fractions which arepoor in aromatics or may be obtained from paraflinicnaphthenic crudeoils. If such oils have a high content of aromatic compounds the oil oroil fraction to be used as feed for the preparation of a base oil shouldfirst be treated in a conventional manner to remove aromatics.

Oil poor in aromatics is understood to mean an oil or oil fraction whichcontains not more than 10% of carbon occurring in an aromatic structure.Preferably the oil contains less than 7% and more preferably less than5% of carbon in an aromatic structure. A suitable feed by means of whichhydrocarbon oils can be obtained as starting material for the process ofthe invention is a waxy distillate of a paraflinic-naphthenic crude oilboiling above 350 C. Alternatively, the fed may be a paraifinic, highlvcatalytically cracked cycle oil boiling for example between 350 C. and510 C. Such a cycle oil should first be wholly or partly freed fromaromatics, for example by extraction with a selective solvent foraromatics in order to obtain a feed which is poor in aromatics. The feedmay also be a de-asphalted residual oil or a fraction thereof obtainedby vacuum distillation of a paraffinic-naphthenic crude oil andde-asphalting of the residue with a lowboiling hydrocarbon such aspropane, butane, pentane or mixtures thereof.

A suitable method for determining whether the feed to be used containsless than 10% of carbon in aromatic structure is by means of infra-redanalysis.

Preference is given to a paraflinic oil boiling above 350 C. which ispoor in aromatics and has a high content of naphthenes with condensedrings. The parafiin content of the oil may be very low; good resultshave been obtained with a paraflin content of less than 20% by weight.In general, use can suitably be made of hydrocarbon oils with a paraflincontent of 50% by weight. Although hydrocarbon oils with a higherparafiin content, for example of 50-75% by weight are suitable for useaccording to the process of the invention there will in general be noneed for them. The content of mononaphthenes in the oil used may varyfrom -50% by weight, the remainder of the oil consisting of di-, tri-,and higher polynaphthenes.

The investigation carried out in connection with the process of theinvention revealed that there is a definite relationship between theviscosity in centistokes at 210 F. (99 C.) and the viscosity index of anoil fraction with regard to the base oils having the same boiling rangeto be prepared therefrom. This relationship for the saturated compoundsof a highly refined aromatic-free paraffinic-naphthenic oil fractionwith a VI of 80 and a viscosity of 8.11 at 210 F. and for the base oilsobtained therefrom according to the invention after removal of thearomatics shows that the portion of the oil fraction which boils above375 C. has a viscosity of about 8.5 at 80 VI which drops linearly toabout 5.2 at 110 VI.

Hence it follows from the aforesaid relationship that starting from agiven oil fraction it is impossible in practice to produce any type ofHVI base oil or lubricating oil. For luboil applications it is desirablehowever that the lubricating oils to be used should combine a high V1with a good viscosity at 210 F. In addition there is the fact that thehigher the viscosity index the lower will be the yield of base oil withthis VI and boiling in the same range. Consequently, continued refiningand/or distillation of the base oil may lead to a product with very highVls but the yield is small. In the production of lubricating oil therefiner will therefore have to compromise between an economicallyjustified yield and the maximum attainable VI consistent therewith.

Using a given parafiinic-naphthenic hydrocarbon oil or oil fraction asstarting material, the process of the invention now makes it possible toprepare base oils with a high VI and a relatively high viscosity at 210F. with a good yield of base oil. Without wishing to be tied down by anyparticular theoretical explanation applicants believe that according tothe process the monoand polynaphthenes are split open to give parafiinsand naphthenes with a lower number of condensed rings, respectively, butwith retention of substantially the same molecular weight. Furthermoredealkylation will take place but cracking will occur to a minor extentonly. As a result of the described reaction the content of parafiinicand mononaphthenic hydrocarbons in the treated base oil with rise. Theuse of the process according to the invention has therefore theadvantage that the polynaphthenes which are detrimental to thelubricating properties of the lubricating base oils are converted intocompounds of a more parafiinic nature without involving a large drop inmolecular Weight. Since the viscosity of an oil is dependent on thepresence of high-molecular compounds a base oil with a good viscositywill be obtained, while the increase in the quantity of parafiins at theexpense of the naphthenes causes a relatively sharp rise in theviscosity index of the base oil. At the same time an improved yield ofHVI base oil is obtained.

In addition to ring-opening of the naphthenes, dehydrogenation of thenaphthenes to aromatics also takes place in the process according to theinvention. The higher the reaction temperature used the higher will bethe aromatics content of the resultant base oil. The aromatics formedcan be removed in a conventional manner such as by liquid extraction,hydrogenation or adsorption on solid adsorbing agents, if this isdesired for the preparation of lubricating base oils with very highviscosity indices.

The alkali metal or alkaline earth metal-containing alumina used ascatalyst carrier preferably contains not more than 4% by weight ofalkali or alkaline-earth and more preferably the alumina contains0.05-2.5% by weight of alkali or alkaline earth. Good results have beenobtained in particular with 0.050.5% by weight. The alkali metal used ispreferably sodium or potassium. Further, the alumina used should behalogen-free. As basic carrier use can be made of any commerciallyavailable alumina which has an alkali or alkaline earth content withinthe specified range. However, if the commercial product is non-basic orhas a relatively high content of halogens such as chlorine and/orfluorine, it can first be treated with steam, hot water or ammonia.After drying and/ or calcination the desired content of alkali metal oralkaline earth metal can be applied by subjecting the alumina to atreatment with an alkali metal or alkaline earth metal salt solution ina manner known per so such as impregnation or percolation. On thecarrier thus prepared, preferably after it has been dried and/ orcalcined, the platinum metal is deposited by means of impregnation withor percolation of a solution of a soluble platinum salt. After havingonce more been dried and calcined the catalyst is ready for use.

It should be noted that the catalyst is used in the form in which theplatinum is present on the carrier as platinum metal. The reduction ofthe platinum compound to platinum metal by means of hydrogen usuallytakes place in the reactor prior to the actual process for theconversion of paratfinic-naphthenic hydrocarbon oils into the desiredbase oil.

As catalyst carrier use is preferably made of an alumina obtained bymeans of an alkali-free mode of preparation and the alkali metal oralkaline earth metal content of which is adjusted by applying thecalculated amount of alkali metal or alkaline earth metal as describedabove. As example of an alkali-free mode of preparation reference may bemade to hydrolysis of aluminium trichloride by means of ammonia.Aluminas of this type are commercially available; if their chlorinecontent is too high they can be made substantially free of chlorine bymeans of a steam treatment. The deposition of the desired alkali metalor alkaline earth metal content is preferably effected after calcinationof the alumina. The alkali metal or alkaline earth metal is preferablydeposited by using the corresponding carbonate solution.

The parafiinic-naphthenic oil is preferably passed over the basiccatalyst at a partial hydrogen pressure below kg./cm. A pressure of50-75 kg./cm. was found to be highly suitable. However, the pressure tobe employed should be in excess of 10 kg./cm. because with pressureslower than 10 kg./cm. there is only dehydrogenation of the naphthenesinto aromatics and no ring opening to form valuable paraffiniccomponents. The liquid hourly space velocity used may vary from 0.5 to 5litres of feed per litre of catalyst per hour, while a hydrogen/feedratio of IOU-10,000 normal litres of hydrogen per litre of feed can beconveniently used.

Preferably a temperature of 375450 C. is used. The higher thetemperature used the better will be the dehydrogenation reaction withthe formation of aromatics. It is advisable therefore to select theremaining reaction conditions in such a manner that the lowest possibletemperature can be employed.

The process according to the invention can be used with a hydrocarbonoil which contains 5000' p.p.m. of sulphur. The effect of using sulphuris two-fold, on the one hand it reduces the activity of the catalyst sothat with the conversion remaining unchanged a higher temperature isrequired and therefore a higher production of aromatics, while on theother hand a base oil is obtained which after removal of aromatics showsa higher VI than without the use of sulphur although the yield is lower.Consequently, the use or non-use of sulphur according to the process ofthe invention enables the refiner to produce particular grades oflubricating oil, depending on demand.

As noted previously, the hydrocarbon oils which are used as startingmaterial for the production of a base oil according to the inventionshould first be free from aromatics if any are present. These oils canbe made poor in aromatics by extraction of the aromatics with aselective solvent such as phenol, sulphur dioxide, furfural, sulpholaneand the like or by means of selective adsorption with a solid adsorbingagent such as silicagel, activated carbon, attapulgus clay or the like.This is a conventional method known in the art. It is also possible tomake aromatic hydrocarbon oils poor in aromatics by means of catalytichydrogenation of the aromatics into naphthenes. Within the scope of thepresent invention a hydrogenation of this type is preferred since thisis beneficial to the ultimate yield of base oil based on the startingmaterial. If in addition the aromatic oil also contains sulphurcompounds in an undesirable quantity, hydrogenation offers the advantagethat these sulphur compounds are removed simultaneously.

If a starting material is available as feed for the process of theinvention which is rich in aromatics and poor in sulphur or if such afeed has already been freed from sulphur in another way, suitablecatalysts for the hydrogenation of aromatics are for example thecommercially available hydrogenation catalysts. Examples of suitablecatalysts are those which contain nickel or metals of the platinum group(or their compounds). As examples may be mentioned a nickel-kieselguhrcatalyst with 40-65% by weight of nickel, a rhodium on alumina catalystwith 0.5% by weight of rhodium or a platinum on aluminum catalyst withfor example 0.1-2% by weight of platinum.

If simultaneously with the hydrogenation of aromatics sulphur compoundsare to be removed, the catalyst used is preferably a desulphurizationcatalyst, in particular catalyst, in particular catalysts which areinsensitive to hydrogen sulphide. Suitable desulphurization catalystsare formed by the metals and/or their oxides or sulphides from the 6thand/or 8th Group of the Periodic Table, supported preferably on asuitable refractory, oxidic carrier with a large surface area.Preferably use is made of catalysts which contain cobalt, molybdenum,tungsten, nickel or their combinations, in the form of their oxides orsulphides. Suitable carriers are formed by alumina, silica, magnesia,boria, zirconia and the like or combinations thereof such assilica-alumina, silica-boria or silicamagnesia. Use can also be made offullers earth, kieselguhr or activated carbon.

It will be clear that the desulphurization catalysts discussed above canalso be used if the hydrocarbon oils to be processed are only to befreed from sulphur compounds.

During the hydrogenation of aromatics, in particular when using theaforesaid desulphurization catalysts, it is essential that crackingreactions and consequently reduction of the molecular weight of theparaffinic-naphthenic feed oil should be prevented as much as possible.To this end use will preferably be made of weakly acidic catalystcarriers and/or the operation will be carried out under such conditionsthat cracking reactions are suppressed.

The hydrogenation of aromatics and/ or the desulphurization can becarried out at temperatures and pressures which may vary within Widelimits. As examples may be mentioned pressures varying from 20-275kg./cm. in particular from 60250 kg./cm. and temperatures of 200-540 C.,in particular of 300-524 C. For a combined hydrogenation of aromaticsand desulphurization the temperature and pressure employed will usuallybe such as to ensure that both reactions lead to an optimum effect. Asuitable temperature and pressure are 400 C. and 200 kg./cm.respectively.

The liquid hourly space velocity during the hydrogenation of aromaticsand/or the desulphurization and the hydrogen/oil ratio may likewise varywithin wide limits. As examples may be mentioned liquid hourly spacevelocities of 0.25-5 litres of oil per litre of catalyst per hour and ahydrogen/oil ratio of -5000 normal litres/litre.

As source of hydrogen for the processes discussed above as well as forthe process of the invention pure hydrogen or for example waste gasesoriginating from catalytic reforming processes may be used.

In the process of the invention aromatics are also formed. Depending onthe desired luboil application the resulting base oil can be treated toremove aromatics by one of the methods discussed above.

From the reaction product obtained according to the process of theinvention the desired base oil is isolated as the product boiling above350 C, preferably above 375 C. The resultant base oil as such may beused as lubricating base oil or it may be split into two or morelubricating base oils by fractional distillation. The base oil or thelubricating base oils may now be subjected, if desired, to any of thetreatments customarily used in the production of lubricating oils inorder to improve the quality, such as improvement of the colour and/ orcolour stability, and reduction of the pour point and/ or aromaticscontent. Such treatments are acid treatment, clay treatment, mildhydrogen treatment, dewaxing, removal of aromatics and the like. Withregard to the dewaxing it may be noted that the removal of parafiin(wax) by means of dewaxing may also be effected with the hydrocarbon oilor oil fraction prior to carrying out the process of the invention.

The process according to the invention may be carried out in any mannerdesired. It is possible for example to use a fluidised catalyst bed or afixed bed; the oil to be treated together with the hydrogen may bepassed through the bed in an upward or a downward direction while theoil and/or hydrogen may or may not be recycled. Such techniques arewidely known and need no further description here.

The invention will be elucidated by the following examples. As iscustomary for lubricating oils the viscosity of the hydrocarbon oils isgiven at a temperature in degrees Fahrenheit. After the hydrogentreatment over the catalyst of the invention the fraction boiling above375 C. which is invariably isolated from the reaction product as thedesired base oil. The content of saturated com pounds in this base oilis determined after removal of aromatics by means of percolation of thesaid fraction over silicagel.

EXAMPLE I The effect of the basicity of the carrier material on theactivity and selectivity of the catalyst according to the invention isdemonstrated by this example.

A series of Pt/Al O catalysts with a varying sodium content in thecarrier material was tested by passing a highly refined oil fractionwhich was free of aromatics and of which 97.5% by weight boiled above375 C., over the individual catalysts together with hydrogen. Allcatalysts contained 1 part by weight of platinum (metal) to 100 parts byweight of carrier.

The platinum had been deposited on the carrier by impregnating thealumina with an aqueous solution of tetrammineplatinum (II) hydroxide.After impregnation the alumina was dried at 120 C. and calcined in airat 500 C. for 3 hours. After calcination the platinum was reduced toplatinum metal by means of hydrogen.

Three alumina carriers with a varying sodium content were examined,namely a commercial alumina with a low sodium content (0.07% by weight),a commercial alumina with a higher sodium content (0.4% by weight) andan alumina obtained by impregnating a commercial alumina with a Na CO-so1ution in order to raise the sodium content (2.4% by Weight).

The reaction conditions employed were as follows: pressure 50 kg./cm.liquid hourly space velocity 1.0 litre of feed per litre of catalyst perhour; H feed ratio 2000 normal litres/litre. The results obtained aswell as of the composition and some properties of the feed used aresummarized below.

FEED Properties: Cs. Viscosity at 100 F. 74.71 Viscosity at 140 F. 26.6Viscosity at 210 F. 8.11 Viscosity index 80 Composition: Percent byweight Parafiins 14 Mononaphthenes 27 Dinaphthenes 23 Trinaphthenes 17Tetranaphthenes 1 1 Pentanaphthenes 4 Hexanaphthenes 1 Balance 3 BASEOIL Carrier material of the catalyst A1203 plus A120; plus A120 plus2.4% \v. of 0.4% w. of 0.07% w. of Na Na Na Reaction temperature, C 420385 380 Product boiling above 375 0.: Yield, percent w. based on feed65. 4 63. 65. 3 Viscosity at 210 F., cs 6. 42 7.08 7. 00 Viscosity index85 88 89 Saturates in product boiling above 375 0.:

Yield, percent w., based on product bo ng above 375 C 71. 8 88. 9 80. 9Viscosity at 210 F., cs 6. 25 6. 88 6. 82 Viscosity index 97 94 93Composition of the saturates,

percent by Weight:

Parailins 22(+8) 28(4-14) 24(+10) Mononaphthenes 20(+2) 32(+5) 28(+1)Dinaplitlieues 21(-2) 17(6) 20(3) Trinaphthenes 15(2) 12(-5) 14(3)Tetranaphthenes 8(3) 7 2-4) 9(2) Pentanaphthenes 4(0) 3 1) 4(0)Hexanaphthenes 1( 0) 1( 0) 1( 0) The results obtained show that theviscosity index of the product boiling above 375 C. is improved by atleast points as compared with the starting product. On further refiningof the resultant product it is found that especially the yield ofsaturates in the product obtained by using a catalyst with 0.4% byweight of Na in the carrier is high, while the viscosity index of theoil is good.

The table also shows the relative increase or decrease of the varioussaturated components in relation to the feed used.

EXAMPLE II This example demonstrates the effect of an increase in theplatinum content of the catalyst.

Viscosity index of product boiling above 375 C. at

a yield oi 50% by 60% by 70% by weight, weight weight, Platinum content,parts by weight to based based based 100 parts by weight of eairier onfeed on feed on feed The results show that at a higher platinum loadingof the catalyst, at the same yield of product boiling above 375 C. ahigher VI is obtained.

EXAMPLE III This example demonstrates the effect of the pressure on theprocess according to the invention.

In order to ascertain the effect of the pressure, the pressure wasvaried in a series of experiments while the temperature was selected insuch a manner that the yield of product boiling above 375 C. amounted toapproximately 65% by weight, based on the feed. The catalyst usedconsisted of 2 parts by weight of Pt on 100 parts by weight of A1 0 thecarrier material containing 0.4% by weight of sodium. The feed used andthe other reaction conditions were the same as reported in Example I.The results obtained are summarized below:

Reaction conditions:

Pressure, kgJcm. 50 75 100 200 'Iemperature, C 375 375 400 400 Productboiling above 375 0.:

Yield, percent w. based on feed 65. 8 67. 2 64. 9 67.5 Viscosity at 210F., cs G. 69 6. 78 6. 16 7.38 Viscosity index 90 89 88 Saturates inproduct boiling above 375 Yield, percent w. based on product boilingabove 375 C 88 8 93. 0 02. 5 96. 2 Viscosity at 210 F., 05.... 6. 41 6.35 7.13 Viscosity index 96 04 88 From the results shown it is found thata pressure of 50 to 75 kg./cm. is an optimum pressure. The optimumeffect of the pressure is especially apparent from the saturatedcompounds in the product boiling above 375 C. Although the yield ofsaturates in this product increases at the higher pressures used, theviscosity index drops sharply which is indicative of a diminishingdehydrogenation of naphthenes in addition to a reduced opening of thering.

EXAMPLE IV This example demonstrates the effect of other metals thanplatinum.

For purposes of comparison experiments were carried out with rhenium andpalladium as active metals. The feed and the other reaction conditionswere similar to those of Example I. The results obtained as well as thetemperature employed are listed below.

Catalyst composition Sulphur content in feed 50 500 5, 000

Pol/A1203 Res/A1203 Pt/AlzOa Reaction temperature, C 385 410 420 42011/100 1.9/10 20/ Product boiling above 375 6.; parts by parts by p tsby Yield, percent w. based on wt. wt. wt. v iced 63.0 63.6 59.4 02.1iscoslty at cs 7.08 6.37 5.71 5.88 Na-content, percent by weight 0. 4 0.4 0. 4 Viscosity index 88 87 02 90 Saturates in product boiling Reactiontemperature, C 420 325 375 ab ve 375 0.; Product boiling above 375 0.:Yield, percent w. based on Yield, percent w. based on feed. 69.1 66. 365.8 product boiling above Viscosity at 210 F., cs 6. 53 8.80 0. 69 1O375 C 88. 9 69. 7 67. 8 70.5

Viscosity index 82 64 91 6. 88 6. 02 5. 51 5.81 saturates in productboiling above Viscosity index St 104 108 109 375 0.: Composition of thesaturates,

Y1eld percent w. based on percent by weight;

product boiling above 315 0 48.7 88.8 Parafiins 2s +14 22 +s 25 +1123(+e) Viscosity at 210 F-, 05 8. 3 6- Mononaphthenes 32(+5) 30( 3) 29(2) 3l( 4) Viscosity index 8 97 Dinaphthcues 17(-6) 21(2) 20(Triuaphtheges 12(5) 14(3) 13(-4) 12(3) The results given show that theuse of Pd or Re as active j Q21? 1 &1; .13;

metal component results in catalysts with a low selectlvrty.Hexanaphthenes 1( 0) EXAMPLE V The eifect of the carrier material usedis apparent from this example.

Under otherwise identical conditions as in Example I From h results h It'f be f that the Of and using the same feed three experiments werecarried Sulphur y f base 0115 i hlgh V15 but that the Yield out with Ptcatalysts which had different carriers. The P saturates In these base0115 has p y droplmd-P111111er results Obtained as Well as someproperties of the carrier 25 1t can be seen that the use of sulphurdecreases the actnvty material used as listed below. of tha catalyst Thetable also shows the relative mcrease or decrease of the varioussaturates in relation to the feed used.

Carrier material EXAMPLE VII a ag This example demonstrates the effectof a steam treatb g E ment of the carrier material.

32%,; 3%,; A commercially available alumina with a relatively 0 6" 0 38high chlorine content (0.28% by weight) was subjected to a steamtreatment in order to remove the chlorine. 9x19; 1. 26 18 To thematerial thus treated which had a chlorine content of 0.03% by weight,0.4% b weight of sodium was Y Sodium int oduced du ing p epa q g a i hadded by impregnation with a Na CO -solution. The imall sgg m deposltedon carrier yimpre nationa ter ca cine 1on0 t e pregnated alumina wasused for the preparation of a 40 platinum-containing catalyst (1 part byweight of Pt to CATALYST COMPOSITION 100 parts by weight of carrier) ina conventional manner Carrier material by impregnation with a solutioncontaining a platinum compound. After previous reduction with h dro enthe B o 5 Pt-content, parts by Weight to 100 part by finished catalystobtamed after drying and calcmation was Welght Gamer 1 1 tested underthe same reaction conditions by means of ges tio n te peregure, 22 385380 420 the feed of Example I. The results obtained are listed 1'0 11001 nga 0V9 .2

Yield, percent w., based on feed 63. 0 63. 4 63. 5 belQW' Viscosity at210 F., cs 7. 08 6. 47 6. 40

Viscosity index 88 91 82 Satufirfatis1 in produtct boilbing aibove 875;C 50 1e percen w. ass on pro uc boiling above 375 0 8s. 9 87. 3 70. 6ggggggpgggyg egggeg by N a 410 Viscosity at 210 F-, CS 88 13 20 Productboning gq 6 Viscosity index 100 92 Yield percent w based oii feud 62Composition of the saturates, percent by viscosity at cs K WeighViscosity index. 88

{P g gz i Satnrates in product boiling above 375 0.: Z f 17 8 Yield,percer21h)yy.F based on product boiling above 375 0.- 79.2 Tn'naphthenes1 12 5 ,f,3i '3 Tetranaphthenes-n 7( 4) Composition ofthesattaa'ysti-atn't"its ht" Pentanaphthenes.-. 3( Pal-ailing Y g g +1Hexanaphthenes m 'gg 'j 26( 1) Dmaphthencs... 19(4) ritnaphtllisgedn14Egg e ranap enes- 8 The catalyst based on carner material B is foundto Icntanaphthenes 4(0) produce the best results both in terms of theviscosity Hexanaphthenes 100) index for the product boiling above 375 C.and in terms of the saturates in this product.

The table also shows the relative increase or decrease 65 The resultsObtflmed nst a e that the alumina of the various saturates in relationto the feed used.

EXAMPLE VI treated with stem and subsequently impregnated is also a goodcarrier material for catalysts according to the invention. A good yieldof product boiling above 375 C. is obtained, while the content ofsaturates therein is high.

The table also shows the relative increase or decrease of the varioussaturated components in relation to the feed used.

EXAMPLE VIII In this example the feed used is a de-asphalted residualoil. A de-asphalted residual oil, obtained by de-asphalting a shortresidue of a Middle-East crude oil with propane, was treated withhydrogen in the presence of a molydenum/nickel on alumina catalyst forthe hydrogenation of any aromatics present, with simultaneous removal ofsulphur and nitrogen compounds, and was subsequently passed withhydrogen over a catalyst according to the invention. The properties ofthe feed and of the products obtained after the first and second processsteps were determined by using the oil obtained after dewaxing sam plesof feed and product with a methylethyl ketone/ toluene mixture. Theresults obtained as well as the reaction conditions used are tabulatedbelow.

1st process step 2d process step Viscosity index S-contcnt, percent by wght Total Nconteut, p.p.msaturates in oil boiling above 375 Yield,percent by wt. based on dewaxed oil boiling above 375 C 29. 79.1 62. 765. 4 Viscosity at 210 F, cs 10. 5 11. 9 8. 2 5.0 Viscosity index 106112 127 148 Composition of the saturates, percent by eight:

Parallins 33 22 43 55 Mononaphthcnes 30 35 33 28 Dinaphthenes 10 23 10Trinaphthenes 11 13 6 4 Tetranaphthenes- 5 5 3 3 Pcntanaphthenes 2 1I-Iexanaphthen% The above results, which are obtained in a once-throughoperation, show that it is possible to prepare a base oil with arelatively high content of saturates and a VI of more than 100 bystarting from a de-asphalted residual oil with a low content ofsaturates and a VI of lower than 80. It is even possible to prepare abase oil with a VI of 131 but in this case the yield, based onde-asphalted oil, is correspondingly lower. By subjecting the base oilsto further refining (removal of aromatics) lubricating oils can beobtained with a VI of 127 and 148.

The decrease in yield of dewaxed oil boiling above 375 C. is partlyattributable to the lighter products boiling below 375 C. which havelikewise formed during the hydrogenation of the aromatics.

EXAMPLE IX In this example the feed used was a de-asphalted residual oilwhich oil had been obtained by de-asphalting a short residue of aMiddle-East crude oil with propane. It was treated with hydrogen in thepresence of a molybdenum/nickel on alumina catalyst for thehydrogenation of any aromatics present, with simultaneous removal ofsulphur and nitrogen compounds, and was subsequently passed withhydrogen over a catalyst according to the invention. The properties ofthe feed and of the products obtained after the first and second processsteps were determined by using the oil obtained after dewaxing samplesof feed and product with a methyl-ethyl ketone/ toluene mixture. Theresults obtained as well as the reaction conditions used are tabulatedin the following table:

2d process step 1st process stlep i A1203: Na: Pt

CatalylstJ composition, parts by AlzOszMo:

weig :11.7:3.1 100:0. 4:1. 0

Reaction conditions:

Temperature C 20 20 40 Pressure, kg. cm. 200 50 Liquid hourly spacevelocity 1.1.- .l1.- 1.0 1.0 Hz/feed, normal litres/litre 2, 000 2, 000

After After Feed 1st step 2d step Dcwaxed oil boiling above 375 0.:

Yicls, percent w., based on deasphalted oil 83. 2 38. 9 31. 4 21. 2Viscosity at 210 F., cs. 43. 3 12. 5 8. 5 5. 3 4. 2 Viscosity index 76122 134 S-eontent, percent by wei 2. 5 0.02 Total N-content, p.p.m. 7

Saturates in oil boiling above 375 0.:

Yield, percent by wt. based on dewaxed oil boiling above 375C. Viscosityat 210 F., cs 19. 5 Viscosity index Composition of the saturates,percent by weight:

Parailins Trinaphthenesm Tetranaphthencs.

We claim:

1. A process for the production of lubricating base oils having highviscosity index wherein mononaphthene and polynaphthene rings are openedto produce parafiins and naphthenes having a lower number of condensedrings while retaining substantially the same molecular weight whichcomprises contacting a parafiinic-naphthenic hydrocarbon oil boilingabove 350 C. and having an aromatic content of less than 7% weightcarbon in an aromatic structure, a paraffin content of 550% weight, amononaphthene content of 1050% weight, a high content of condensed ringnaphthenes and a sulfur content of 0-5000 p.p.m.w. with hydrogen in thepresence of a basic catalyst comprising more than 0.5% weight platinummetal supported on a halogen-free alumina containing not more than 4%weight of an alkali or alkaline earth metal at a hydrogen partialpressure of above about 10 kg./cm. and a temperature of at least 345 C.

2. The process of claim 1 wherein the alkali or alkaline earth metalcontent of the alumina is from 0.05 to 2.5% weight sodium or potassiumand the catalyst contains from 15% weight platinum metal.

3. The process of claim 2 wherein the hydrogen partial pressure is from50 to 75 kg./cm. and the temperature is from 375-450 C.

4. The process of claim 3 wherein the paraflinicnaphthenic hydrocarbonoil contains less than 5% weight carbon in an aromatic structure and thealkali or alkaline earth metal content of the alumina is from 0.05 to0.5 weight.

References Cited UNITED STATES PATENTS 2,779,711 l/1957 Goretta 2081432,944,014 7/ 1960 Holfman 208264 3,142,635 7/1964 Coonradt et a1. 208183,331,769 7/1967 Gatsis 208264 3,425,932 2/1969 Surrena et al 2081433,432,565 3/1969 Kouwenhoven et a1. 208143 2,915,452 12/1959 Fear 208573,395,196 7/1968 Heckelsberg 260-683 3,431,198 3/1969 Rausch 208143HERBERT LEVIN Primary Examiner US. Cl. X.R. 20 8--1 8

